In motor vehicles running in the lower speed range, particularly at idling, the entire vehicle is often subject to low-frequency vibrations. These vibrations are in the range of between 1 and 5 Hz.
The reason for these vibrations lies in the series production of the fuel-injection equipment. The injection components are manufactured to tolerances causing different quantities of injected fuel per cylinder. These differences in fuel quantity result in rapid torque changes which excite the vibratory composite of engine and chassis. Thus, the vibrations are an unavoidable consequence of manufacturing tolerances.
These low-frequency vibrations may be dampened, for example, by correcting the amounts of fuel to be injected into the individual cylinders. Such an apparatus for dampening the vibrations includes, for example, a regulator which, in dependence on rapid torque changes, varies a predetermined desired fuel value in such a manner to keep these torque changes at a minimum possible level.